We describe our investigation of the effectiveness ofWeb content negotiation using CC/PP. CC/PP is a proposed specification on a user-side content negotiation framework to comply with various clients. CC/PP is based on common technologies such as XML and HTTP extension and is expected to provide a generic content negotiation solution, but neither its performance nor effectiveness has ever been shown. We have implemented a CC/PP capable Web browser and a CC/PP proxy, and measured the performance of CC/PP and various different settings. The result shows that the use of indirect reference and abbreviating profile-diffs have good improvements on retrieval time when the client connection is as narrow as cellular phones. When the connection is faster than that, the use of inline encoding would be better provided that the profile size is less than a certain threshold, in our tests, approximately one-tenth the value of effective bandwidth of the client connection. The observed traffic with content conversion by CC/PP was smaller than the case without CC/PP for all tested environments, and the retrieval time is better or comparable for cellular phone clients. The result confirms that CC/PP is an effective solution for general content negotiation.